1. Field of the Invention
The present invention relates to optical pickup devices used for writing data on or reading data from optical storage media such as CDs (compact discs), DVDs (digital versatile discs), BDs (Blu-ray discs, trademark), and so forth. The invention also relates to methods for manufacturing such optical pickup devices.
2. Description of the Related Art
Optical pickup devices are used to write data on or read data from optical storage media such as CDs, DVDs, and BDs. Typically, an optical pickup device includes an optical system designed to guide the light emitted from a light-emitting device (e.g., laser diode) to an objective lens via lenses, a prism, a mirror, and other devices, thereby focusing the light onto an optical storage medium. The pickup device also include another optical system for allowing a photoelectric converter, which converts optical output into electric signals, to receive the light reflected from the optical storage medium via various lenses, a prism, a mirror, and other devices.
Among such components is the actuator including the objective lens. As illustrated in FIG. 7, a tilt adjusting holder 102 holds an objective lens 101. The tilt angle of this tilt adjusting holder 102 needs to be adjusted relative to an objective lens holder 105. Referring now to FIG. 7, tilt adjustment for the tilt adjusting holder 102 is discussed below.
Several methods exist to adjust the tilt angle of the tilt adjusting holder 102. One is to create a reference surface within the tilt adjusting holder 102 so that the position of the objective lens 101 can be adjusted in a direction of the optical axis (i.e., in the top or bottom direction of FIG. 7) and in a direction vertical to the optical axis. Once the position is set based on the reference surface, the objective lens 101 is glued to the tilt adjusting holder 102. Another is to provide a seat section 108 on the objective lens holder 105 such that the seat section 108 faces the outer surface of the tilt adjusting holder 102. Once the tilt angle of the tilt adjusting holder 102 is adjusted relative to the seat section 108 of the objective lens holder 105, the tilt adjusting holder 102 is glued to the objective lens holder 105 with an adhesive 107.
Typically, adhesive is not applied after the position of the tilt adjusting holder 102 has been set. Instead, to facilitate the task, the adhesive 107 is applied in advance to the adhesive joint sections of the objective lens 101 or to the adhesive joint sections of the tilt adjusting holder 102 or to the seat section 108. Tilt adjustment is then conducted for the tilt adjusting holder 102 to which the objective lens 101 has been glued with an adhesive 103. After the tilt adjustment, the adhesive 107 is cured, thereby securing the tilt adjusting holder 102 to the objective lens holder 105.
Examples of such a method include the method of JP-A-2006-338811 and the method of JP-A-2008-176887, in both of which a tilt adjusting holder is used for an actuator.